1. Field of the Invention
This invention relates to an ink jet printer.
2. Description of the Prior Art
Among conventional ink jet printers, there is one type which is provided with a carriage which is transportation means movable in a predetermined direction relative to a recording surface and in which recording is effected with the carriage carrying one or more liquid discharge recording units. In the conventional ink jet printer of this type, an ink tank has been provided as an ink container for containing ink to be supplied to the liquid discharge recording unit or units fixed to the printer body and the ink has been supplied to the liquid discharge recording unit or units through an ink supply system including a supply pipe. In such a construction, however, the amount of so-called creep of the ink supply pipe has been great with the distance between the ink tank and the liquid discharge recording unit or units taken into account and accordingly, the mixing of air with the supply path has been liable to occur, and this has led to a problem that accurate ink discharge may not be effected. Also, particularly in an ink jet printer provided with a plurality of liquid injection recording units, there arises a problem that the piping of the ink supply system becomes complicated.
Further, during recording, the distance between the liquid discharge recording unit carried on the carriage and the ink tank fixed to the apparatus body is varied and therefore, a tube formed of a material of high flexibility such as vinyl chloride or polyethylene must be selected as the supply pipe. Generally, such a soft supply pipe readily permits the mixing of air and therefore, the above-noted problems may become more serious.
Also, among the ink jet printers of this type, there is one in which, when bubbles are mixed with the liquid discharge recording unit or when the nozzle portion thereof is clogged, the carriage is positioned at a predetermined position which is not opposed to the recording surface, for example, a home position, and ink is sucked from the nozzle portion by a suction mechanism disposed at that position to thereby eliminate the bubbles or the clogging.
In such an ink jet printer, it has been a task to reliably discharge the ink sucked by the suction mechanism without leakage and moreover enable the discharged ink to be readily discarded from the ink jet printer.
Further, in such an ink jet printer, when the sucking process is to be effected, the suction mechanism must effect the process of moving cap means joined to the ink discharge portion of the liquid discharge recording unit toward the ink discharge portion and the process of driving suction means for sucking the ink from the ink discharge portion in the joined state. Thus, it would come to mind to connect those means to respective drive sources and drive the drive sources at an appropriate timing to thereby effect a series of sucking processes.
According to this, however, the number of drive sources increases in accordance with the number of driven means and therefore, not only will the apparatus become bulky and expensive, but also there will arise a problem that the control system for timing the driving will become complex.
Also, it is preferable to provide locking means for fixing the liquid discharge recording unit to the suction mechanism throughout such a series of sucking processes and holding appropriate junction.
Thus, it would come to mind to connect those means to respective drive sources and drive the drive sources at an appropriate timing to thereby effect the series of sucking processes while holding the junction.
Again in this case, however, the number of drive sources increases in accordance with the number of driven means and therefore, not only will the apparatus become bulky and expensive, but also there will arise a problem that the control system for timing the driving will become complex.